This invention relates to a recording and/or reproducing device represented by DLT (digital linear tape) or LTO (linear tape open) and, in particular, to a recording and/or reproducing device comprising a driving mechanism for driving a pull-out assembly so as to house it in a reel hub of a take-up reel.
Recording and/or reproducing devices of the type described are developed for use in back-up ones of computer systems and various types of the recording and/or reproducing devices have been proposed in prior art. Such a recording and/or reproducing device serving as the LTO is disclosed, for example, in the patent document WO 00/30093 A1.
The recording and/or reproducing device may be also a tape drive in which a cartridge having a single reel (a supply reel) can be installed. The cartridge may be also called a cassette. The recording and/or reproducing device contains a take-up reel therein. When the cartridge is installed in the recording and/or reproducing device, a magnetic tape is pulled out of the cartridge and then is wound by the take-up reel through a tape-transport path. The tape-transport path is for guiding the magnetic tape pulled out of the cartridge in a magnetic head. The magnetic head exchanges information between the tape and the magnetic head. In addition, the take-up reel is rotationally drivable by means of a real motor.
In the manner which is disclosed in the above-mentioned patent document WO 00/30093 A1, the cartridge comprises a housing, a rotationally drivable supply reel accommodated in the housing, the magnetic tape wound onto the reel hub of the supply reel, and a coupling element which is connected to the magnetic tape in the free end area of the magnetic tape and which is held in a coupling position. The coupling element is also called a leader pin.
In order to enable the magnetic tape contained in the cartridge to be wound onto the take-up reel, the magnetic tape should first be brought to the take-up reel with the aid of the leader pin. For this purpose, the recording and/or reproducing device has a pull-out element. The pull-out element is adopted to be coupled to the leader pin. The pull-out element is also called a grabber.
In order to enable the grabber to be coupled to the leader pin, the recording and/or reproducing device includes retaining means adapted to detachably retain the grabber. The retaining means are movably between a standby position and an operating position. A movement of the retaining means into their operating position causes a movement of the grabber in a coupling direction and the grabber and the leader pin to be coupled. On the other hand, a movement of the retaining means out of their operating position causes a movement of the grabber in a direction opposite to the coupling direction and the grabber and the leader pin to be disengaged.
In order to enable the grabber and the leader pin, after they have been coupled, i.e. a pull-out assembly thus formed, to be moved away from the retaining means an to be moved up to the reel hub of the take-up real, the recording and/or reproducing device includes actuating means. The actuating means are simply formed by a pull-out tape. The pull-out tape is guided along the above-mentioned tape-transport path. The pull-out tape is also called a leader tape.
In a conventional recording and/or reproducing device, the reader tape has one end connected to the grabber and its other end connected to a reel hub of the take-up reel. Thus, by driving the take-up reel in a take-up direction using a reel motor, the pull-out assembly can be moved away from the retaining means up to the reel hub of the take-up reel with the aid of the reader tape in a simple manner. The reel hub and the pull-out assembly are brought to each other. A combination of the take-up reel and the reel motor is called a tack-up mechanism.
In the manner which is described above, the patent document WO 00/30093 A1 discloses the recording and/or reproducing device (the tape drive) using the reader tape. In such a recording and/or reproducing device, the take-up reel comprises the reel hub, an upper reel flange which is integral with the reel hub, and a lower reel flange which is connected to the reel hub by means of an adhesive joint or by means of an ultrasonic weld. The pull-out assembly can be moved away from the retaining means to the real hub of the take-up reel by means of rotation of the pull-out tape (the leader tape) in a predetermined direction, in order to bring the reel hub and the pull-out assembly into engagement. In order to make this possible, the reel hub has a shape which differs from a circularly cylindrical shape in that a portion having the shape of circular segment is missing. When the reel hub of the take-up reel and the pull-out assembly have been brought into engagement, a partly cylindrical circumferential surface of the reel hub and a partly cylindrical circumferential surface of the pull-out assembly together from a cylindrical winding surface onto which the magnetic tape can be wound.
The recording and/or reproducing device disclosed in the patent document WO 00/30093 A1 comprises a radial direction positioning means between the reel hub of the take-up reel and the pull-out assembly. The radial direction positioning means comprises two projecting portions wherein a first projecting portion projects from the reel hub and a second projecting portion projects from the pull-out assembly.
In such a recording and/or reproducing device using the reader tape, in order to read/write data from/in the magnetic tape with stability, it is necessary to takes-up the magnetic tape on the take-up reel irrespective of the presence or absence of the leader tape. In the recording and/or reproducing device disclosed in the patent document WO 00/30093 A1, the leader tape is directly wound on the reel hub of the take-up reel.
Therefore, the recording and/or reproducing device disclosed in the patent document WO 00/30093 A1 has problems as follows. It will be assumed that the leader tape is thick and firm or the take-up reel has week winding force. Under the circumstances, it is disadvantageous in that there is uneven in winding because the magnetic tape is not wound along the reel hub of the take-up reel. Conversely, it will be assumed that the leader tape is thin. In this event, it is disadvantageous in that it is difficult to handle and durability is low.
On the other hand, a tape threading apparatus for use with a single reel cartridge of source tape is known, for example, in U.S. Pat. No. 6,227,475 issued to Jeffrey S. McAllister at al. The tape threading apparatus allows leader tape to be spooled onto in inner leader drum, and source tape to be spooled on to an outer take-up drum. The tape threading apparatus has a take-up reel having an outer drum configured to accept source tape. The tape threading apparatus further includes a leader drum which is supported essentially concentric with and at least partially rotatable with respect to the outer drum. The leader tape has a first end attached to the leader drum and a second end provided with a tape connector which can be connected to the source tape. The outer drum has a leader tape opening to allow leader tape to pass freely from the leader drum to the outside of the outer drum. The leader tape opening is configured to prevent passage of the tape connector therethrough. In a first embodiment, the leader drum is configured to be driven by a drive motor. Engagement of the tape connector into the tape opening causes the force imparted on the leader drum by a drive motor to be imparted to the outer drum, causing the outer drum to rotate and spool the source tape onto the outer drum. In a second embodiment, the tape threading apparatus further includes a spring having a first connection point connected to the leader drum and a second connection point connected to the take-up reel. Extension of the leader tape from the take-up reel causes compression of the spring such that when the source tape is connected to the tape connector and released, the spring causes the leader tape to be spooled onto the inner leader drum and the tape connector to be engaged into the opening in the outer drum. Thereafter, rotation of the outer drum will cause the source tape to be spooled onto the outer drum.
In the tape threading apparatus according to McAllister et al., the tape connector must substantially form a part of a cylindrical magnetic tape taking-up surface when the tape connector (a leader block) is received in the leader tape opening. Otherwise, a winding winkle of the magnetic tape may occur because the reel hub of the take-up reel has not cylindrical shape with precision. As a result, it is difficult to make the magnetic tape run at a constant speed. Accordingly, it is necessary to manufacture the tape connector (the leader block) and the leader tape opening with accuracy and it is necessary to position the tape connector in the leader tape opening with precision.
Other recording and/or reproducing devices using a pantocam arm or a threader arm in lieu of the leader tape are known, for example, in U.S. Pat. No. 6,067,211 issued to Alex Chliwnyj et al. or in Japanese Unexamined Patent Application Publication Tokkai No. H11-328635 or JP-A 11-328635.
According to Chliwnyj et al., the recording and/or reproducing device employs a pantocam arm which carries a leader pin for capturing a leader block, the leader block being attached to the magnetic tape to be processed. After capturing the leader block, the pantocam arm swings the leader block around an arcuate tape guide and then lodges the leader block in a take-up reel. When the take-up reel is rotated, the magnetic tape moves adjacent the magnetic head, the magnetic head being located intermediate the tape guide. After the magnetic tape is processed, a supply reel in the cartridge returns the magnetic tape to the cartridge and the pantocam arm delivers the leader block to the cartridge, where it is released.
In the recording and/or reproducing device using the threader arm disclosed in JP-A 11-328635, the threader arm comprises a driving arm which is rotatably driven by a driving portion such as a motor and a follower arm relatively rotatably coupled to the driving arm. The follower arm has a tip to which a threader pin is fixed. By driving the driving arm after the cartridge is inserted in the recording and/or reproducing device, the threader pin engaged with the leader block of the cartridge carries the leader block toward a machine reel (a take-up reel). On taking the cartridge out of the recording and/or reproducing device, the threader pin carries the leader block from the machine reel (the take-up reel) to the cartridge along a guide groove.
In either of those two recording and/or reproducing devices disclosed in U.S. Pat. No. 6,067,211 and JP-A 11-328635, one surface of the leader block forms a portion of the magnetic tape winding surface in the reel hub of the take-up reel when the leader block is received in the take-up reel (the machine reel).
That is, in the recording and/or reproducing devices using the pantocam arm or the threader arm, the reel hub of the take-up reel is provided with a reader block receiving slot which has a shape matching that of leader block (the pull-out assembly) (for example, see U.S. Pat. No. 4,334,656 issued to Roy P. Crawford et al.). The slot extends from the outer periphery of the reel hub radially inward past the axis of rotation a sufficient distance to position the axis of a coupling pin (the reader pin, the threader pin) coaxially with the axis of rotation of the take-up reel. With the coupling pin so positioned, the leader block is free to rotate relatively to the coupling pin as magnetic tape is wound on the take-up reel. In addition, an automatic tape threading apparatus disclosed in U.S. Pat. No. 4,334,656 comprises a driving mechanism (a driving system) for driving the leader block. The driving mechanism is for moving the coupling pin from a first position where it is selectively coupled and uncoupled from the leader block to a second position in the substantial center of the take-up reel. In the manner which is described above, the coupling pin is disposed substantially coaxial with the axis of rotation of the take-up reel so that rotation of the take-up reel, and hence, the leader block can occur without any adverse affect on the coupling pin.
In the recording and/or reproducing devices disclosed in U.S. Pat. No. 6,067,211 and JP-A 11-328635, as disclosed in U.S. Pat. No. 4,334,656, it is necessary to substantially position the axis of the coupling pin (the leader pin, the threader pin) coaxially with the axis of rotation of the take-up reel when the leader block (the pull-out assembly) is received in the reel hub of the take-up reel. That is, the coupling pin is used as a shaft of the take-up reel. However, U.S. Pat. No. 4,334,656 neither discloses a concrete structure or way how to substantially position the axis of the coupling pin (the shaft) coaxially with the axis of rotation of the take-up reel. That is, U.S. Pat. No. 4,334,656 does not disclose positioning means for the coupling pin (the shaft).
In addition, in order to rotate the take-up reel and the leader block (the pull-out assembly) without any adverse effect on the coupling pin (the shaft), it is necessary to make the axis (a center) of the coupling pin (the shaft) exact coincide with the axis (a center) of rotation of the take-up reel. However, the centers of both do not generally coincide with each other caused by unevenness of parts and/or assembly. Therefore, when the take-up reel rotates at a high speed, wearing occurs between the leader block (the pull-out assembly) and the coupling pin (the shaft), and then it is feared that a position relationship between the leader block (the pull-out assembly) and the coupling pin (the shaft) changes. Under the circumstances, it may have an adverse affect on the durability of the driving mechanism because the afore-mentioned driving mechanism is subjected to periodic motion through the coupling pin (the shaft).
In order to resolve this problem, those skilled in the art may consider a method of absorbing the above-mentioned unevenness of parts and/or assembly by setting clearance between the coupling pin (the shaft) and the leader block (the pull-out assembly). However, in motion under the condition, for example, of vibration, the coupling pin (the shaft) may move from a predetermined position due to the clearance of the driving mechanism and the coupling pin (the shaft) may be in contact with the leader block (the pull-out assembly). It is therefore not enough because collision and wearing occur between the coupling pin (the shaft) and the leader block (the pull-out assembly) when the take-up reel rotates at a high speed.
Accordingly, after the leader block (the pull-out assembly) is received in the reel hub of the take-up reel, a reliable method is required to prevent rotation of the take-up reel and the leader block (the pull-out assembly) from having any adverse affect so that the coupling pin (the shaft) is out of contact with the leader block (the pull-out assembly) on rotating the take-up reel.